Are you the same "you" that went to sleep last night? (Thought experiment: what if we die every night we go to bed? Seriously consider this for a moment.)

Are "you" a "you" at all?

What if "you" is just a prediction machine linked to prediction capability + history + planning + objectives + online learning? Your memories are just seasoning for the weights?

Personality, nostalgia and frisson are just hallucinations of experience. Biochemical complexity feels alive and conscious in large numbers and at scale, but it's all simple physics.

Microtubule dynamic instability etc. etc. is just how evolution stumbled upon a runtime learning algorithm. It's not the only solution.

RE the first question I'm sure someone hasn't seen this yet:

https://existentialcomics.com/comic/1

Subjectively though, sleep 'feels' like it maintains continuity in a way. But of course that could just be a rationalization.